Selective hammer interposing means in high speed printers



July 25, 3937 J. c. SW15, JR 3,332,343

SELECTIVE HAMMER INTERPOSING MEANS IN HIGH SPEED PRINTERS Filed June 20, 1966 N I 9 u.

: INVENTOR JOHN C.S!MS,JR

EZW LM ATTORNEY United States Patent 3,332,343 SELECTIVE HAMMER INTERPOSING MEANS IN HIGH SPEED PRINTERS John C. Sims, J12, Sudbury, Mass, assignor to Anelex Corporation, Boston, Mass, a corporation of New Hampshire Filed June 20, 1966, Ser. No. 559,000 Claims. (Cl. 101-93) This invention relates to printing devices and, in particular, to devices wherein printing is accomplished by actuating hammers for coaction with selected character type faces.

Hammer-actuated printers of various types are well known, such as the devices shown and described in US. Patent No. 2,805,620 to Leo Rosen, Howard C. Barlow, and Ray L. Bowman, entitled, Control Means for High Speed Printing Apparatus, and issued Sept. 10, 1957. In this patent, a separate hammer is associated with each character position along the printing line and a rotating drum containing rows and columns of type faces which are continuously moved past the printing line to effect printing when the hammers are actuated.

In order to reduce the cost of printers, numerous devices have been proposed which reduce the number of hammers required, such as the devices shown and described in US. patent application Ser. No. 178,371, by David F. Sweeny, entitled, High Speed Printers, and filed Mar. 8, 1962. These devices utilize wide hammers that effect printing in several character positions by successive actuation as type faces are moved past the character positions. In these devices, type faces are presented in only one character position at a time for each hammer, resulting in restraints on the operation of the system. For example, when the type faces are engraved or mounted on the surface of a drum with one column of type faces for each printing position, the circumference of the drum must be large enough to accommodate the desired num ber of type faces multiplied by the number of character printers that are controlled by each hammer. These restraints can be avoided without increasing the number of hammers by utilizing single-character width hammers, each for several columns, and by laterally shifting the document through several printing cycles, as shown and described in US patent application Ser. No. 426,034, to Robert H. Curtiss, entitled Printing Machine Incorporating Spaced-Font Print Roll and Method of Printing, and filed Jan. 18, 1965.

The present invention provides the advantages of the various above-described devices WithOUt either restraining the operation of the type carrier or requiring document shifting mechanisms. This is accomplished by utilizing a type carrier which presents type faces to all printing positions at the same time (as in the Rosen et al. patent) in conjunction with an improved hammer mechansim. In the present invention, each hammer mechanism contains a drive hammer which is several characters in width and an interposing hammer which is one character in width. During a first cycle, the interposer hammer is activated by the drive hammer to print in one selected character position, then the interposer hammer is moved to another character position and again activated by the same drive hammer to effect printing in that position during a second cycle. In the preferred embodiment of the invention, each drive hammer is four characters in width, so an entire line is pirnted in four cycles. After each line is printed, the document is moved, bringing the next line to be prined into position. The interposer hammer is returned to its first position while the document is being moved. If desired, the interposer hammer can be moved in opposite directions during the printing of successive lines at ice the expense of complicating the control mechanism. In the preferred embodiment of the invention, the type is mounted on a drum, but with obvious modifications, other type carriers can be used, such as train or chain type carriers, where the same set of type is moved past all character positions in the printing line.

It is thus a primary object of the present invention to provide an improved printing device.

Another object is to provide an improved printing device employing multiple-character width drive hammers and interposer hammers.

A further object is to provide an improved printing device wherein sequential printing takes place in a group of character positions through the use of a movable inter= poser hammer in conjunction with a single drive hammer.

The foregoing and other objects, features and advantages of the invention will be apparent from the following more particular description of a preferred embodiment of the invention, as illustrated in the accompanying drawings.

In the drawings:

FIGURE 1 is a cut-away diagram showing the structure of a preferred embodiment of the invention.

FIGURE 2 is a diagram showing details of a hammer mechanism that is suitable for use in the preferred embodiment of the invention.

The inventive hammer arrangement is shown in a drum printer environment in FIG. 1, where type faces 10 are engraved in rows and columns on the surface of a drum 11. The document to be printed and the printing ribbon which for simplicity are locted directly below the drum.

11 are not shown. During the continuous rotation of the drum, hammer mechanisms are selectively activated to force the document and ribbon against the desired type faces to effect printing.

Referring to FIG. 2, the hammer mechanism comprises a plurality of drive hammers 13 and interposer hammers 15. In the preferred embodiment of the invention, the drive hammer has a width W which is equal to four printing positions on the document (four columns of type faces on the drum). The interposer hammer 15 is one character position (column) in width. As shown in FIG. 2, the interposer hammer is located adjacent to the rightmost quarter of the surface of the drive hammer 13. After printing one character on the drum, the interposer hammer is shifted toward the left to a position adjacent to the position shown in FIG. 2, and a second character is printed on the document. Similarly, a third and a fourth character are printed as the interposer hammer is moved to a third position and finally to a fourth (leftmost) position. Thus, four characters are printed on the document by four successive actuations of each drive hammer 13.

The interposer hammer 15 is preferably formed from spring steel with the tip folded back (as shown in FIG. 2) to provide a clearly defined hammer region. However, other hard flexible materials can be used, such as stainless steel, beryllium copper or titanium.

Returning to FIG. 1, a group of drive hammers 13 is aligned along the line to be printed. While the drive hammer actuating mechanism is not critical, in FIG. 1 two hammers are mounted in each module 17 and the hammers are electromagnetically actuated. Suitable hammer actuating mechanisms are shown in copending US. application Ser. No. 327,201, by Humbert C. Russo, entitled Print Hammer Assembly for High Speed Printers, and filed Dec. 2., 1963, which issued as US. Patent No. 3,266,418.

All interposer hammers 15 are arranged for simultaneous shifting movement. In the preferred embodiment, as shown in FIG. 1, the interposer hammers are formed as part of an integral mounting element 19. The ends 21 of the mounting element 19 are bent at right angles and connected to the rear of the hammer mechanism by screws 23. Since the mounting element 19 is formed from spring steel, the entire interposer assembly is free for shifting movement along the direction of the line of hammers. As described above, the interposer hammers are shifted between printing cycles such that the entire line of printing is effected in four cycles. The interposer hammers are not shifted to another position until all of the character positions corresponding to the present position have been printed (every fourth position along the line of printing).

The position of the interposer hammer assembly is controlled by a wrap-around spring clutch 25 and cam follower 27. An input element 29 of the spring clutch is continuously rotated by a shaft 31 which is mounted in a bearing 33 and driven by a belt 35 on a pulley 37. An output element 39 of the clutch rotates under the control of a pivoted arm 41 and a ratchet 43. The arm 41 is pivoted about a fixed axis out of engagement with the ratchet 43 after each revolution of the drum 11 under the control of conventional. timing circuits, such as shown in US. Patent No. 3,142,247 to David F. Sweeney, entitled Control System for High Speed Printers, filed on Mar. 8, 1962, and issued on July 28, 1964. Four ratchet surfaces are equally distributed around the clutch. When the pivoted arm 41 is momentarily raised, the output element of the clutch rotates 90 and the next ratchet surface is encountered. The cam follower mechanism. 27 is controlled by the output element of the clutch through a shaft 45 mounted on a bearing (not shown).

The interposer hammer assembly is connected to a control arm 47, the other end of which is mounted for sliding motion in a bushing 49. The control arm is broken to show the cam follower components including two follower wheels 51 and a cam surface 53. One follower wheel 51 is located on each side of the cam surface 53 and the wheels are arranged for rotational movement about a pair of axles 54 which are mounted on the control arm 47. Thus rotation of the cam surface 53 (under control of the output element 39 of the clutch) causes the :arm 47 to move laterally in conformance with the shape of the cam surface 53. The cam surface 53 follows a smooth curve which joins four points whose distances from its center of rotation differ by equal increments. That is, as the cam follower rotates through its four positions (each separated by 90 as determined by ratchet surfaces 43) the arm 47 is shifted through three equal displacements and then returned to its original position. The control arm 41 is controlled by a solenoid or other means to cause the 90 rotation of the cam follower after each printing cycle is completed.

The spring clutch and cam follower that are used in the preferred embodiment of the invention can obviously be replaced by many other well-known positioning devices.

While the invention has been particularly shown and described with reference to a preferred embodiment thereof, it will be understood by those skilled in the art that the foregoing and other changes in form and details may be made therein without departing from the spirit and scope of the invention.

What is claimed is:

1. A printing device comprising, in combination:

means for presenting a set of type to each of a plurality of character positions along a printing line; and a hammer mechanism for coacting with the presented type to effect printing;

the hammer mechanism comprising a plurality of drive hammers arranged along the printing line, each having a width along the printing line essentially spanning a plurality of character positions, an interposer hammer for each drive hammer, each interposer hammer arranged between its associated drive hammer and the presented type, having a width essentially spanning at least one character position, and movable in the direction of the printing line to each of the character positions corresponding to the associated drive hammer, and means for sequentially moving the interposer hammers to permit printing of successive character positions.

2. The device described in claim 1, wherein the type presenting means is drum shaped and rotates about an axis that is parallel to the printing line.

3. The device described in claim 1, wherein each drive hammer has a width that is approximately equal to the distance along the printing line that encompasses four character positions and each interposer hammer has a width that is approximately equal to the distance along the printing line that encompasses one character position.

4. The device described in claim 1, wherein the interposer hammer is sequentially moved in a first direction during the printing of each line and is returned in the opposite direction between the printing of lines.

5. The device described in claim 1, wherein all interposer hammers are moved in unison under the control of a cam mechanism.

References Cited UNITED STATES PATENTS 2,766,686 10/1956 Fomenko et al 10193 2,805,620 9/1957 Rosen et a]. 10193 2,831,424 4/1958 MacDonald 10193 3,128,693 4/1964 Thiemann 10193 3,135,195 6/1964 Potter 10193 3,188,947 6/1965 Paige 10193 3,253,539 5/1966 Christotf et al 10193 3,266,418 8/1966 Russo 10193 WILLIAM B. PENN, Primary Examiner. 

1. A PRINTING DEVICE COMPRISING, IN COMBINATION: MEANS FOR PRESENTING A SET OF TYPE TO EACH OF A PLURALITY OF CHARACTER POSITIONS ALONG A PRINTING LINE; AND A HAMMER MECHANISM FOR COACTING WITH THE PRESENTED TYPE TO EFFECT PRINTING; THE HAMMER MECHANISM COMPRISING A PLURALITY OF DRIVE HAMMERS ARRANGED ALONG THE PRINTING LINE, EACH HAVING A WIDTH ALONG THE PRINTING LINE, EACH SPANNING A PLURALITY OF CHARACTER POSITIONS, AN INTERPOSER HAMMER FOR EACH DRIVE HAMMER, EACH INTERPOSER HAMMER ARRANGED BETWEEN ITS ASSOCIATED DRIVE HAMMER AND THE PRESENTED TYPE, HAVING A WIDTH ESSENTIALLY SPANNING AT LEAST ONE CHARACTER POSITION, AND MOVABLE IN THE DIRECTION OF THE PRINTING LINE TO EACH OF THE CHARACTER POSITIONS CORRESPONDING TO THE ASSOCIATED DRIVE HAMMER, AND MEANS FOR SEQUENTIALLY MOVING THE INTERPOSER HAMMERS TO PERMIT PRINTING OF SUCCESSIVE CHARACTER POSITIONS. 